There are at least two major iso-enzymes of amylase in blood and urine, P (pancreatic) derived from the pancreas and S (salivary) derived largely from the salivary glands, but possibly from other cellular tissues. In addition there are a number (possibly four) of minor iso-enzymes. These iso-enzymes may be measured by conventional electrophoretic or iso-electric focusing techniques. The present study proposes to investigate the following: (A) the diagnostic value of estimating iso-amylases, i.e. whether quantitative iso-enzyme measurement will in fact be superior to routine total amylase determinations in acute and chronic pancreatitis, cystic fibrosis, carcinoma of the pancreas, and hyperamylasemic state and serially in patients with pancreatitis to identify chronicity. The amylase clearance ratio at present applied to total amylase activity will be reviewed with regard to P specific amylase clearance and the effect of renal disease, hepatic disease and diabetes on the iso-enzymes will be studied,; (B) a number of physiological and experimental studies on iso-amylase activity will be undertaken. These include (1) the effect of feeding and/or secretin-CCK provocation on blood, urine and pancreatic juice, S and P iso-amylases; (2) efforts to determine the "pancreatic amylase reserve" or "pancreatic acinar mass" (PAM) by measuring blood and urine P amylase after serially increasing pancreatic resection in the animal; and (3) a comparison between blood P and S amylase values with bicarbonate, amylase and trypsin concentrations in duodenal juice obtained at pancreatic function testing; and (C) a comparision between the two methods for fractionating amylase with regard to accuracy, reproducibility, the time factor involved, etc. with the purpose of delineating the feasibility of introducing iso-enzymes as a routine laboratory procedure; and (D) an attempt to simplify the method of P amylase determination by S amylase extraction on varying exchange resins.